Category Archive: Services

Cleanroom HVAC Systems 101


Founded in 1953, Liberty Industries has since established itself as a premier manufacturer and distributor of cleanroom and contamination control supplies and accessories. Equipped with almost seven decades of industry experience, we can design, build, and install some of the highest quality cleanrooms with top-of-the-line components, including cleanroom HVAC systems.

The following blog post provides an overview of HVAC systems for cleanrooms, outlining design basics and key design considerations.

HVAC systems for cleanrooms

The Basics of HVAC Design

Heating, ventilation, and air conditioning (HVAC) is an umbrella term for the systems used to maintain conditions—e.g., temperature, airflow, and humidity—within indoor areas. They are used in industrial, commercial, and residential facilities to ensure environmental conditions are comfortable and optimal for the necessary operations. When integrated into cleanrooms, they are critical to the maintenance of air quality levels for applications involving sensitive materials or requiring the containment of potentially hazardous materials.

Conventional and cleanroom HVAC systems have some overlapping functions—i.e., enabling industry professionals to control temperature, humidity, and airflow to achieve comfortable living and working conditions. However, the HVAC systems for cleanrooms also perform more advanced functions—such as monitoring and maintaining air supply and flow patterns, filtering out contaminations, and preserving pressure differentials—to ensure the enclosed area is suitable for sensitive and/or dangerous material operations.

The design of a cleanroom HVAC system changes depending on the requirements and restriction of the application, including  ISO classification , temperature, humidity, and pressure specifications.  Some of the key components include:

  • Air handling units (AHUs)
  • Air ducts
  • High-efficiency particulate air (HEPA) filters
  • Air diffusers
  • Air return pathways and equipment
  • Air quality monitoring and control systems

Considerations During the Design Phase

When designing and planning a cleanroom, there are several factors to keep in mind to ensure the finished structure meets the needs of the application. While designs may vary depending on the operations performed within the cleanroom some of the key considerations include:

Airflow Capacity

The airflow capacity of a cleanroom (indicated in cubic feet per minute) affects how many air changes are performed per hour. This characteristic, in turn, depends on several factors, such as the cleanliness level required, the number of personnel and equipment/supplies, the size and number of rooms, and the movement of the people and materials into and out of the cleanroom. While commercial HVAC systems perform less than two air changes per hour, cleanroom HVAC systems generally do 10 to 600 air changes per hour. The higher air change frequency is necessary to prevent particles from settling in the cleanroom.

Airflow Pattern

Airflow patterns within cleanrooms generally take one of three forms: laminar (unidirectional), turbulent (non-directional), or mixed-flow. The pattern appropriate for a cleanroom depends on the design and application.

Pressure Differential

Cleanrooms are available in positive pressure or negative pressure variations. Positive pressure cleanrooms are used to keep contaminants out, while negative pressure cleanrooms are designed to keep potentially hazardous materials in.

Employees and Equipment

Both employees and equipment are sources of contamination for cleanrooms. When brought in or out, they may allow particulates and pollutants to come into the controlled environment or hazardous materials to escape into the outside environment. With this in mind, cleanroom personnel must commit to rigorous health and safety protocols such as wearing the correct personal protective equipment (PPE), going through decontamination areas and bringing in or out only cleared supplies and materials.

Other factors that employees influence include the number of air changes required per hour (more employees mean more air changes) and the temperature levels (cleanroom temperature must be within comfortable levels for human operators).

Cleanroom Layout

The layout of a cleanroom affects the efficiency and effectiveness of the HVAC system. For example, the positioning of equipment and air input/output points can help or hinder the filtration of particulates.

Design Considerations for Cleanrooms

Design and Construct Your Cleanroom With Liberty Industries

For all your cleanroom needs, turn to the experts at Liberty Industries. We provide cleanroom design, construction, and installation services as well as all related supplies and accessories to deliver a complete solution.

For additional information about our cleanroom capabilities, download our eBook or contact us today. To receive pricing details, request a quote with your cleanroom requirements.


A Guide to Cleanroom Cleaning & Maintenance


At Liberty Industries, we build high-quality cleanrooms with customizable designs. We offer myriad products to create specialized environments and offer complete installation services. Since 1953, we have been providing industrial companies comprehensive solutions and contamination control supplies, including those pertaining to cleanroom cleaning. 

Cleanrooms use a variety of mechanisms to reduce the risk of contamination, such as vertical flow component systems for airflow and Tacky Mats® that capture dirt and dust. Regular cleaning and maintenance of cleanrooms ensures optimal operation so products don’t fail inspection and research results don’t become contaminated.

How to Clean a Cleanroom

Dirt, dust, and contaminants may enter even the most carefully controlled cleanroom as people enter and exit, with material shipments, and more. There are two main categories of contaminants: physical contaminants generated by the cleanroom itself, and process or human action contaminants from cleaning, the movement of goods, and particulates from skin and hair. Floors, work areas, walls, ceilings, and vents must be wiped down during and after each session to keep the environment sterile and secure.

Cleanroom floors can easily become contaminated over time as dust and other particulates settle. At Liberty Industries, we recommend that facilities regularly follow a comprehensive process to clean floors. This process should include the following:

  • Vacuuming the surface to remove any loose dirt and debris.
  • Next, rinse the floor with deionized water and a certified cleansing solution to break up films or dried contaminants. 
  • Once the floor is dry, vacuum it again to remove every trace of debris disturbed during the mopping process. 
  • For larger cleanrooms, it’s important to change the water between rooms or every 15 square feet to reduce the risk of cross-contaminating separate spaces.

Companies should also implement preventative measures to reduce contamination in the first place. These steps include Tacky Mats®, air showers, and shoe covers that keep debris from reaching the cleanroom environment in the first place.

The floor isn’t the only surface that suffers from contamination. It’s just as important to wipe down work surfaces, gowning areas and benches, pass-thrus, walls, and windows. Vertical surfaces can capture contaminants circulated through the air and may also become contaminated at high touch points. 

We recommend using wipes and sponges that are specifically designed for cleanroom applications. These cleaning tools have less breakable fibers and are much less likely to create debris. Lint-free 70% IPA wipes, in particular, present minimal risk of debris. HEPA filter hand dryers are also available.

Liberty Industries distributes cleaning materials for a variety of different cleanroom environments. We carefully source and recommend products that help our customers maintain their cleanroom’s rating. Some of the products we provide include:

  • LIB8312 Sterile IPA  30/70, 12 oz, 16/cs
  • CRF440 Cleaning agent, 20 oz 
  • 8025 Econowipe, 9 x 9 wipes, 6 tubs/cs, 300 per tub 
  • LN-10 Urethane sponges
  • HEPA filter vacuums such as our CRV 7347 model

Additional Cleanroom Maintenance

Keeping your cleanroom in spec should be one of your facility’s top priorities. Additional steps your team can take to ensure high-quality production and testing conditions include:

  • Instituting a regular schedule of daily, weekly, and monthly cleaning tasks.
  • Using polycarbonate shields when lubricating equipment that prevent the lubricant from contaminating the space.
  • Maintaining positive-pressure airflow before, during, and after cleaning procedures.
  • Keeping detailed records about acceptable margins of contamination and the cleanroom’s adherence to standards of cleanliness.
  • Ensuring workers having the necessary gowns, gloves, shoe covers, and other shielding materials to reduce contamination during cleaning procedures.
  • Create detailed plans and assign responsibility for each cleaning task so your cleanroom is never in violation of cleanliness standards.

Cleanroom Construction, Maintenance, and Support From Liberty

Cleanrooms require a lot of care and maintenance to keep them operating in accordance with regulations and industry standards. At Liberty Industries, we don’t just create and install cleanrooms. We can provide our customers with the tools and cleaning supplies to assist them in maintaining their required cleanroom needs. 

Contact our team or request a quote for more information about best practices and leading products for cleanroom maintenance and cleaning.


cleanroom maintenance checklist


Is a Controlled Environment the Same as a Cleanroom?


Liberty Industries has prominently put itself forward as a manufacturer and supplier of high-quality cleanroom and contamination control products for customers around the world since 1953. We are pleased to offer a broad range of customizable products for controlled environments and cleanrooms, so our customers are sure to find everything they need in one place. Our wide range of critical environmental products include cleanrooms, air showers, fan filter units, pass-thrus, laminar flow benches, shoe brushes, Tacky Mats®, and a variety of accessories such as vacuums and cleanroom clothing. 

In order to ensure that you choose the best facility and equipment for your critical environment needs, it is important to have a clear understanding of the difference between a controlled environment and a cleanroom. Although both environments have similar traits, a cleanroom must follow more rigorous regulations and standards.

Is There a Difference Between a Controlled Environment and a Cleanroom?

Cleanrooms and controlled environments are very much alike, but the specifications for each differ in severity. While controlled environments largely entail the control of factors such as air pressure and temperature, cleanrooms require these environmental controls plus decontamination and filtration. For this reason, cleanrooms require a great deal of specialized design and equipment that is not necessary in a controlled environment.  

Controlled Environment

A controlled environment, also known as a critical environment, is a space with precisely regulated environmental factors. Air temperature, temperature, and humidity are regulated to meet operational needs, and the critical area is isolated from other operations within the facility. The level of particle contamination is not measured and controlled environments are not required to meet the same high decontamination standards as cleanrooms. 


Cleanrooms are used to create a particulate free environment free of contaminants such as dust, mold, and microorganisms. They are actually a type of controlled environment and must still maintain rigorous environmental control and segregation from external environments. 

However, the environmental conditions within the cleanroom must adhere to much more stringent regulations. For example, cleanrooms are required to meet certain standards for the acceptable volume of particle contaminants in the air. This means that specialized filtration and cleaning technology must be employed to different degrees, depending on the application and industry for which the cleanroom operates.

The level of decontamination is determined based on the classification required for the industry and application. Cleanroom standards come from a variety of sources, including;

  • Good Manufacturing Practices (GMP)
  • Food and Drug Administration (FDA)
  • Deutsches Institut für Normung (DIN)
  • European standards (EN)
  • International Organization for Standardization (ISO) 14644-1 

ISO 14644-1 establishes 9 classifications for particle contamination, wherein Class 1 is the most stringent and Class 9 the least. Depending on the application and industry, standards and regulations will establish the level of acceptable particles per cubic meter, and the acceptable size of those particles, measured in micrometers (μm). 

Choosing the Proper Cleanroom

Cleanrooms for controlled environments are tailored to meet the specific needs of the industry and application they serve. Cleanroom contractors will consider a wide range of factors when determining the construction materials and environmental regulating equipment. In order to ensure that the facility is accurately and thoroughly equipped, the contractor will consider the following:

  • Level of required cleanliness (i.e. ISO class, FDA regulations)
  • Types and placement of filters (HEPA or ULPA)
  • Environmental conditions 
  • HVAC requirements
  • Spatial specifications
  • Construction materials
  • Air showers and/or pass-thru units
  • Fire protection
  • Light and air supply and filtration
  • Electrical and plumbing requirements
  • Equipment hookups and special equipment

Choosing the best cleanroom for your needs means understanding the specific requirements for your industry. Cleanrooms are used in a wide variety of industries and applications, including:

  • Pharmaceutical
  • Aerospace
  • Medical
  • Biotechnology
  • Food & beverage

Each industry must adhere to the requirements of its own regulatory bodies, broader industry standards for cleanrooms, and accepted best practices.

Controlled Environment and Cleanroom Equipment and Supplies 

With over 60 years of experience, Liberty Industries understands that each critical environment has very specific needs. Our highly knowledgeable and experienced team of engineers will help you design and tailor your controlled environment equipment and accessories to meet your company needs and the most stringent industry standards. For more information on our critical environment products, contact us today or request a quote


Have Any Questions?

Click Here!